链表：判断一个链表是否为回文结构

/**
 * 
 * @param head ListNode类 the head
 * @return bool布尔型
 */
function isPail( head ) {
    let arr = [],res = []
    let cur = head
    while(cur){
        arr.push(cur.val)
        res.push(cur.val)
        cur = cur.next
    }
    arr.reverse()
    for(let i = 0;i < arr.length;i++){
        if(arr[i] != res[i]){
            return false
        }
    }
    return true
}